Stretchable display panel and stretchable display device including the same

ABSTRACT

A stretchable display device having a pliant substrate and a plurality of rigid substrates positioned on the first substrate spaced a first selected distance apart from each other. The pliant substrate having a having a first modulus of elasticity and the second substrates having a second modulus of elasticity that is greater than first modulus of elasticity. There is a semiconductor circuit have a semiconductor transistor and positioned on each of the rigid substrates. At least some of the rigid substrates also include an organic light emitting diode formed thereon. The pliant substrate is configured to stretch, moving the rigid substrates a second distance apart from each other that is greater than the first selected distance. Electrically conductive lines extend between respective ones of the second substrates, each of the electrically conductive lines being configured to stretch to maintain the rigid substrates electrically connected to each other when spaced the first distance apart from each other and also when they are spaced the second, greater distance from each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.16/712,256, filed Dec. 12, 2019, which claims the priority of KoreanPatent Application No. 10-2018-0171997 filed on Dec. 28, 2018, in theKorean Intellectual Property Office, the disclosure of which isincorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to a display device and, moreparticularly, to a stretchable display device having a display paneltherein that can stretch.

Description of the Related Art

An Organic Light Emitting Display (OLED) that generates light by itself,a Liquid Crystal Display (LCD) that uses separate light sources, andother types of displays are used as the display devices used in acomputer monitor, a TV, and a mobile phone.

Display devices are being used in more various fields including not onlya computer monitor, a TV, personal mobile devices, and also in displaydevices having a large display area with reduced volume and weight.

Recently, a stretchable display device manufactured to be able tostretch/contract in a specific direction and change into various shapesby forming a display unit on a flexible substrate that is a plasticmaterial has been spotlighted as a next generation display device.

BRIEF SUMMARY

Accordingly, the present disclosure is directed to a display panel and astretchable display device that overcomes and compensates for one ormore problems due to limitations and disadvantages of the related art.

One of the objects of the present disclosure is to provide a stretchabledisplay device that can stretch. Another object is to provide a highquality image from the display device while it is being stretched andalso after is has been stretched and returned to its former shape.

Another object of the present disclosure is to provide a stretchabledisplay device in which a plurality of rigid substrates are disposed ona base substrate made of a pliable material and light emitting elementsare formed on some of the rigid substrates, thereby being able to formthe light emitting elements without damaging the circuits and lightelements on the substrates while providing a display that isstretchable. In some embodiments, various drive and control circuitsthat are constructed on rigid substrates are also placed on the samepliable base substrate with the light emitting elements, providing adisplay panel in which the entire panel is stretchable that includes thelight emitting elements, drive elements, control circuits are all othercircuits that make up the display.

Another object of the present disclosure is to provide a stretchabledisplay device that can sense the degree of stretch of the displaypanel. One way to sense the degree of stretch makes use of flexibleconnecting lines electrically connecting a plurality of rigidsubstrates. Another way disposes stretch sensing lines that can sensethe degree of stretch of the display panel.

Another object of the present disclosure is to provide a stretchabledisplay device that can reduce the deterioration of image quality of thestretchable display device. One of the ways to maintain the imagequality at a high level is to sense the degree of stretch of a displaypanel and then generate compensation data in accordance with the degreeof stretch sensed that is applied to the data to each pixel.

Objects of the present disclosure are not limited to the above-mentionedobjects, and other objects, which are not mentioned above, can beclearly understood by those skilled in the art from the followingdescriptions.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the disclosure as claimed.

The present disclosure describes a display device that may be easilybent, flexed or stretched without damaging driving elements and lightemitting elements disposed in a stretchable display device by disposinga plurality of rigid substrates on a base substrate composed of astretchable, pliant or flexible material. The driving and controlcircuits as well as the light emitting elements are disposed onrespective, individual rigid substrates.

The present disclosure may sense the degree of stretch of a substrateusing a connecting line by configuring at least one or more connectinglines of a plurality of connecting lines electrically connecting aplurality of rigid substrates spaced apart from each other on a basesubstrate made of a stretchable material to include two sensing lines.

The present disclosure may use a panel area by configuring at least oneor more connecting lines of a plurality of connecting lines as a stretchsensing line and by configuring one of the sensing lines to be the sameline that transmits a data signal, gate signal, OLED characteristiccorrection signal, or other control signal to each subpixel and to sensethe degree of stretch of a panel.

The present disclosure may sense the degree of stretch of a displaypanel by additionally disposing a stretch sensing line that may sensethe degree of stretch of the display panel over the display panel thatis a different line than a connecting line transmitting a data or gatesignal to respective ones of the plurality of pixels.

The present disclosure enables a display panel to stretch and alsoreduce deterioration of image quality caused by the stretch. One of theways it does this is to create compensation data by comparing a sensedvalue of the degree of stretch and a reference value, and then applycompensation data to each respective pixel. In one embodiment, thestretch at each local pixel is sensed and compensation provided that isdifferent on a pixel by pixel basis. In other embodiments, the degree ofstretch of a group of pixels is sensed and compensation provide for agroup of pixels. In some embodiments, the stretch of the drive andcontrol circuits can be sensed and compensation provided based on thedegree of stretch such circuits experience.

According to one embodiment a stretchable display device is providedhaving a first pliant substrate having a first modulus of elasticity.There are a plurality of second substrates positioned on the firstsubstrate and spaced apart from each other, each of the secondsubstrates being rigid and having a second modulus of elasticity that isgreater than first modulus of elasticity. At least one semiconductortransistor is positioned on each of the second substrates of theplurality. There are electrically conductive lines extending betweenrespective ones of the second substrates, each of the electricallyconductive lines configured to be stretched while remaining electricallyconductive.

In one embodiment, each of the second substrates has a light emittingelement positioned thereon. The electrically conductive lines extendingbetween respective ones of the second substrates is a data line thatprovides a data signal to the light emitting element on the secondsubstrate. The second modulus of elasticity is more than one thousandtimes greater than the first modulus of elasticity.

The electrically conductive lines have a flexible, twisty, wavy shape inone embodiment. The electrically conductive lines have a stretchablediamond shape in another embodiment.

In one embodiment there is a stretch sensor positioned between thesecond substrates. The stretch sensor includes a first capacitor whosevalue remains constant while the stretch sensor is being stretched and asecond capacitor whose value varies in relationship to an amount of thestretch while the stretch sensor is being stretched. The stretch sensoris positioned within one of the electrically conductive lines thatextends between respective ones of the second substrates. At least oneof the electrically conductive lines extending between respective onesof the second substrates is a gate line for the transistor on the secondsubstrate.

In accordance with another embodiment there is a method of using thestretchable display by stretching the first substrate having a firstmodulus of elasticity a first distance. There are a plurality of second,rigid substrates positioned on the first substrate a first distance awayfrom each other. Each of the second substrates has a second modulus ofelasticity that is greater that the first modulus of elasticity. Each ofthe second substrates of the plurality has at least one semiconductortransistor thereon. During a stretching step, the the respective secondsubstrate move a second distant from each other that is greater than thefirst distance during the stretching. The electrical connection betweenthe second substrates is maintained by a stretchable conductive linebetween the plurality of second substrates prior to and after thestretching. In one embodiment, the amount of stretch of the firstsubstrate is measured during the stretching. A stretch compensationsignal is generated based on the measured amount of stretch during thestretching. A light emission data signal is transmitted to the organiclight emitting diodes during the stretching. The light emission datasignal that is transmitted to the organic light emitting diode ismodified during the stretching step based on the generated compensationsignal. A gate drive signal is transmitted to the at least onetransistor on the rigid substrate during the stretching. After a periodof time, the stretching terminates the first substrate returns to theunstretched shape after the stretching.

According to one embodiment, there is a method of making a stretchabledisplay panel that includes providing a first pliant substrate having afirst modulus of elasticity. A plurality of second, rigid substrates,are formed having respective semiconductor transistor circuits on eachof the second, rigid substrates. The second substrates have a secondmodulus of elasticity that is greater than the modulus of elasticity ofthe first pliant substrate. The plurality of second, rigid substrates onthe first substrate are spaced a selected distance apart from eachother. Electrically conductive lines are formed connecting the pluralityof second, rigid substrates to each other with respective electricallyconductive lines. Each of the electrically conductive lines are pliantand has third modulus of elasticity that is less than the second modulusof elasticity.

An organic light emitting diode is disposed on at least some of therespective ones of the plurality of second, rigid substrates. A stretchsensor is formed in at least one of the plurality of electricallyconductive lines connecting the respective ones of the plurality ofsecond, rigid substrates to each other.

The effects according to the present disclosure are not limited to thecontents exemplified above, and more various effects are included in thepresent specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is an exploded perspective view of a stretchable display deviceaccording to an embodiment of the present disclosure;

FIG. 2 is an enlarged plan view enlarging one pixel area disposed in astretchable display device according to an embodiment of the presentdisclosure;

FIG. 3 is a schematic cross-sectional view of one subpixel of astretchable display device according to an embodiment of the presentdisclosure;

FIG. 4 is a schematic cross-sectional view of one subpixel of astretchable display device according to another embodiment of thepresent disclosure;

FIG. 5 is a schematic cross-sectional view taken along line V-V of FIG.2;

FIG. 6 is an enlarged plan view enlarging one pixel area disposed in astretchable display device according to another embodiment of thepresent disclosure;

FIG. 7 is a schematic cross-sectional view taken along line VII-VII′ ofFIG. 6;

FIG. 8 is an enlarged plan view enlarging one pixel area disposed in astretchable display device according to another embodiment of thepresent disclosure;

FIG. 9 is a schematic cross-sectional view taken along line VIII-VIII′of FIG. 8;

FIG. 10 is a schematic plan view for illustrating the configuration ofstretch sensing lines disposed in a stretchable display device accordingto an embodiment of the present disclosure;

FIG. 11 is a cross-sectional view schematically showing oneconfiguration example taken along line a-a′ of FIG. 10;

FIG. 12 is a cross-sectional view schematically showing oneconfiguration example taken along line b-b′ of FIG. 10;

FIG. 13 is a cross-sectional view schematically showing anotherconfiguration example taken along line a-a′ of FIG. 10;

FIG. 14 is a cross-sectional view schematically showing anotherconfiguration example taken along line b-b′ of FIG. 10;

FIG. 15 is a cross-sectional view schematically showing anotherconfiguration example taken along line a-a′ of FIG. 10;

FIG. 16 is a cross-sectional view schematically showing anotherconfiguration example taken along line b-b′ of FIG. 10;

FIG. 17 is a block diagram of a stretchable display device according toan embodiment of the present disclosure; and

FIG. 18 is a flowchart sequentially showing an image compensation methodof a stretchable display device according to an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Advantages and characteristics of the present disclosure and a method ofachieving the advantages and characteristics will be clear by referringto exemplary embodiments described below in detail together with theaccompanying drawings. However, the present disclosure is not limited tothe exemplary embodiments disclosed herein but will be implemented invarious forms. The exemplary embodiments are provided by way of exampleonly so that those skilled in the art can fully understand thedisclosures of the present disclosure and the scope of the presentdisclosure. Therefore, the present disclosure will be defined only bythe scope of the appended claims.

The shapes, sizes, ratios, angles, numbers, and the like illustrated inthe accompanying drawings for describing the exemplary embodiments ofthe present disclosure are merely examples, and the present disclosureis not limited thereto. Like reference numerals generally denote likeelements throughout the specification. Further, in the followingdescription of the present disclosure, a detailed explanation of knownrelated technologies may be omitted to avoid unnecessarily obscuring thesubject matter of the present disclosure. The terms such as “including,”“having,” and “consist of” used herein are generally intended to allowother components to be added unless the terms are used with the term“only”. Any references to singular may include plural unless expresslystated otherwise.

Components are interpreted to include an ordinary error range even ifnot expressly stated.

When the position relation between two parts is described using theterms such as “on”, “above”, “below”, and “next”, one or more parts maybe positioned between the two parts unless the terms are used with theterm “immediately” or “directly”.

When an element or layer is disposed “on” another element or layer,another layer or another element may be interposed directly on the otherelement or therebetween.

Although the terms “first”, “second”, and the like are used fordescribing various components, these components are not confined bythese terms. These terms are merely used for distinguishing onecomponent from the other components. Therefore, a first component to bementioned below may be a second component in a technical concept of thepresent disclosure.

Like reference numerals generally denote like elements throughout thespecification.

A size and a thickness of each component illustrated in the drawing areillustrated for convenience of description and ease of understanding,and the present disclosure is not limited to the size and the thicknessof the component illustrated.

The features of various embodiments of the present disclosure can bepartially or entirely adhered to or combined with each other and can beinterlocked and operated in technically various ways, and theembodiments can be carried out independently of or in association witheach other.

Hereinafter, a stretchable display device according to exemplaryembodiments of the present disclosure will be described in detail withreference to accompanying drawings.

A stretchable display device may be referred to as a display device thatmay display images even if it is bent, flexed or stretched. Astretchable display device may have high flexibility, as compared withcommon display devices. Accordingly, the shape of the stretchabledisplay device may be freely changed in accordance with operation by theuser such as bending or stretching the stretchable display device. Forexample, when a user holds and pulls an end of a stretchable displaydevice, the stretchable display device may be stretched by the force ofthe user. Alternatively, when a user puts a stretchable display deviceon an uneven wall, the stretchable display device may be disposed to bebent in the surface shape of the wall. Further, when the force appliedby a user is removed, a stretchable display device may return into theinitial shape.

FIG. 1 is an exploded perspective view of a stretchable display deviceaccording to an embodiment of the present disclosure. Referring to FIG.1, a stretchable display device 1000 according to an embodiment of thepresent disclosure includes a display panel 100, a flexible connectingfilm 200, and a printed circuit board 300.

The display panel 100 can stretch and contract in any one direction of afirst direction X and a second direction Y or can 2-dimensionallystretch and contract in the first direction X and the second directionY. Here, the first direction X and the second direction Y define theplane of the stretchable display device 1000 and the second direction Ymay be a direction different from the first direction X. For example,the second direction Y may be a direction substantially perpendicular tothe first direction X.

The display panel 100 includes a lower substrate 110 disposed at a lowerportion and an upper substrate 120 disposed on the lower substrate 110.Though not shown in FIG. 1, the display panel 100 may further include apolarizing layer that may be disposed on the upper substrate 120 orunder the lower substrate 110. Further, the lower substrate 110 and theupper substrate 120 of the display panel 100, may be bonded by anadhesive layer.

The lower substrate 110 is a substrate for supporting and protectingvarious components of the stretchable display device 1000. The lowersubstrate 110 may include a first substrate 111 of the lower substrate110 made of a pliable material and being able to stretch and contractand a plurality of second substrates 112 disposed on the first substrate111 of the lower substrate 110 and made of a rigid material more thanthe first substrate 111. Here, the first substrate 111 may be referredto as a base substrate or a flexible substrate and the plurality ofsecond substrates 112 may be referred to as rigid substrates.

The first substrate 111 may be made of an insulating material that maybend or stretch. For example, the first substrate 111 may be made ofsilicon rubber such as polydimethylsiloxane (PDMS) or an elastomer suchas polyurethane (PU), so it may have flexibility. The material of thefirst substrate 111, however, is not limited thereto. The firstsubstrate 111, which is a flexible substrate, may reversibly expand andcontract. Further, an elastic modulus may be several to hundreds of GPafor the Young's Modulus and a tensile fracture rate may be 100% or more.In some embodiments the Young's Modulus or the first substrate is lessthan 100 GPa, while it is in the range of 100 to 1000 GPa in otherembodiments. In some embodiments, it might be in the range of greaterthan 1000 and less than 10,000 GPa. The thickness of the first substrate111 may be 10 μm to 1 mm, but is not limited thereto.

The plurality of second substrates 112 spaced and disposed by apredetermined distance from each other are disposed on the firstsubstrate 111. The plurality of second substrates 112 are substratesthat are rigid more than the first substrate 111 made of a pliablematerial, but also may be flexible substrates with less elasticity. Theplurality of second substrates 112, for example, may be made ofpolyimide (PI), polyacrylate, polyacetate, and the like.

The modulus of elasticity of the plurality of second substrates 112 maybe higher than that of the first substrate 111. The modulus is anelastic modulus showing the ratio of deformation of a substrate tostress applied to the substrate, and when the modulus of elasticity isrelatively high, the material is rigid and it resistance to flexing maybe relatively high. Accordingly, the plurality of second substrates 112may be rigid substrates that are more rigid than the first substrate111. The modulus of elasticity measured as the Young's Modulus of theplurality of second substrates 112 may be a thousand times or morehigher than that of the first substrate 111, but is not limited thereto.For example, the second substrates may be comprised of silicon,sapphire, glass or other rigid material and have a Young's Modulus inthe range of 100,000 to 1,000,000 GPa. In other instances, the Young'sModulus of the second substrate will be in the range of 10,000,000 to100,000,000 GPa. In other embodiments it will be in the range of100,000,000 to 500,000,000 GPa or higher.

A light emitting element and various driving elements for driving thelight emitting element, for example, a switching thin film transistor, adriving thin film transistor, a capacitor, etc. are disposed on each ofthe plurality of second substrates 112. Here, the light emitting elementmay be any one of an organic light emitting element and a micro LED.

In general, a stretchable display device has an easily bending orstretching characteristic, so there have been attempts in the past touse substrates that have a flexible property due to a small modulus.However, when a pliable material such as polydimethylsiloxane (PDMS)having a small modulus is used as the material of a lower substrate onwhich light emitting elements are disposed, a material having a smallmodulus is can become weak due to heat, so, due to this characteristic,there is a problem that the substrate is damaged by high temperature,for example, temperature over 100° C. that is generated in the processof forming transistors and the light emitting elements.

Accordingly, light emitting elements should be formed on a substratemade of a material that can withstand high temperature, so damage to thesubstrate can be avoided in the process of manufacturing light emittingelements. Accordingly, there have been attempts to manufacture asubstrate using materials that can withstand high temperature, which isgenerated in the manufacturing process, such as polyimide (PI). However,materials that can withstand high temperature do not have flexibleproperties due to large moduli, so substrates are not easily bent orstretched when stretchable display devices are stretched. In addition,various types of light emitting elements, transistors and drivingcircuits are often constructed on semiconductor substrates which arefrequently made of silicon that is rigid. If the individual componentsof the transistor, such as the gate, gate dielectric, source, drain andother electrodes flex, this will drastically change the operatingcharacteristics of the transistor and, if flexed too much, will destroythe transistor. It is preferred that some circuit elements of thedisplay device not bend or flex.

Therefore, the plurality of second substrates 112 that are rigidsubstrates are disposed in the areas where transistors or light emittingelements are disposed in the stretchable display device 1000 accordingto an embodiment of the present disclosure, so damage to the stretchabledisplay device 1000 due to high temperature in the process ofmanufacturing the transistors or light emitting elements may beminimized.

Referring to FIG. 1, the plurality of second substrates 112 each may beelectrically connected by connecting lines 180. The connecting lines 180may be electrically connected by connecting pads disposed on each of theplurality of second substrates 112. Here, the pads disposed on each ofthe plurality of second substrates 112 may be, for example, gate pads,data pads, and power pads. Since the connecting lines 180 are disposedon the first substrate 111, they may have a twister or wavy shape topermit them to stretch without breaking. Although the connecting lines180 are shown as having a twisty, wavy shape in an embodiment of thepresent disclosure, they are not limited thereto. The connecting lines180 may have a straight shape, a chevron shape, or a simple way shapedepending on the material of the connecting lines 180. For example, thelines 180 may have a diamond shape that will reduce damage to theconnecting lines 180 due to stretching.

In common display devices, various lines such as a plurality of gatelines and a plurality of data lines are extended and disposed between aplurality of subpixels, and a plurality of subpixels are connected toone signal line. Accordingly, in common display devices, various linessuch a gate line, a data line, a high-potential power line, and areference voltage line extend from a side to the other side of thedisplay devices on a substrate without disconnection.

By contrast, in the stretchable display device 1000 according to anembodiment of the present disclosure, various lines such as gate lines,data lines, high-potential power lines, and low-potential power lines,which are made of a metal material, are disposed on the plurality ofsecond substrates 112. That is, in the stretchable display device 1000according to an embodiment of the present disclosure, various lines madeof a metal material may be disposed on the plurality of secondsubstrates 112 and may not be formed to be in contact with the firstsubstrate 111. Accordingly, various lines disposed in the stretchabledisplay device 1000 may be patterned to correspond to the plurality ofsecond substrates 112 and discontinuously disposed.

In the stretchable display device 1000 according to an embodiment of thepresent disclosure, the pads on two adjacent second substrates 112 maybe connected by the connecting lines 180 to connect the discontinuouslines. That is, the connecting lines 180 electrically connect the padson two adjacent second substrates 112. Accordingly, the stretchabledisplay device 1000 according to an embodiment of the present disclosureincludes a plurality of connecting lines 180 electrically connectingvarious lines such as gate lines, data lines, high-potential powerlines, and reference voltage lines between the plurality of secondsubstrates 112.

The connecting lines 180 electrically connect the plurality of secondsubstrates 112. That is, the connecting lines 180 are disposed inspacing areas of the plurality of second substrates 112. The connectinglines 180 may be disposed between the pads disposed on the plurality ofsecond substrates 112 and may electrically connect each pad. Forexample, though not shown, a gate line made of a metal material may bedisposed on the plurality of second substrates 112 disposed adjacent toeach other in the first direction X and gate pads may be disposed atboth ends of the gate line. The plurality of gate pads on the pluralityof second substrates 112 disposed adjacent to each other in the firstdirection X each may be connected to each other by a connecting line 180functioning as a gate line. Accordingly, the gate lines disposed on theplurality of second substrates 112 and the connecting line 180 disposedon the first substrate 111 may function as one gate line. Further, allvarious lines that may be included in the stretchable display device1000, such as the data lines, high-potential power lines, andlow-potential power lines, also each may function as one line by aconnecting line 180, as described above.

Referring to FIG. 1, the connecting lines 180 may include firstconnecting lines 181 and second connecting lines 182. The connectinglines 180 are pliant and have modulus of elasticity that issubstantially less than the modulus of elasticity of the secondsubstrates 112. In one embodiment, it is greater than the modulus ofelasticity of the first substrate 111. It might be, in some examples,the modulus of elasticity of the connecting lines 180 might be 5 to 10times greater than that of the first substrate 111, while in otherembodiments, it might be 10 to 100 times greater.

The first connecting lines 181 refer to those lines disposed in thefirst direction X on the lower substrate 110. The first connecting lines181 may connect pads on two substrates 112 disposed in parallel of thepads on the plurality of second substrates 112 disposed adjacent to eachother in the first direction X to each other.

The first connecting lines 181 may include a gate connecting linetransmitting a gate signal, a high-potential connecting linetransmitting high-potential power, and a low-potential connecting linetransmitting low-potential power. In addition, the first connectinglines 181 may further include a stretch sensing line configured to sensethe degree of stretch of the lower substrate 110. The first connectinglines 181, particularly, the stretch sensing line will be described inmore detail with reference to FIGS. 6 and 7 in association with astretch sensing function that senses the degree of stretch of the lowersubstrate 110. Meanwhile, although the first connecting lines 181 aredescribed as being composed of a gate connecting line, a high-potentialconnecting line, and a low-potential connecting line in this embodiment,they are not limited thereto.

The second connecting lines 182 refer to those lines disposed in thesecond direction Y on the lower substrate 110. The second connectingline 182 may connect pads on two substrates 112 disposed in parallel ofthe pads on the plurality of second substrates 112 disposed adjacent toeach other in the second direction Y to each other.

The second connecting lines 182 may be data connecting linestransmitting a data signal to each subpixel. In some embodiments, atleast one data connecting line of the data connecting lines thattransmit a data signal to each subpixel, that is, the second connectinglines 182 may be configured to be able to sense the degree of stretch ofthe lower substrate 110 and transmit a data signal. Meanwhile, althoughthe second connecting lines 182 are described as data connecting linesin an embodiment of the present disclosure, they are not limitedthereto. The second connecting lines 182 will be described next in moredetail with reference to FIGS. 2 to 5.

Meanwhile, as another embodiment, though not shown in FIG. 1, the secondconnecting lines 182 may further include a stretch sensing lineconfigured to sense the degree of stretch of the lower substrate 110. Inthis case, the second connecting lines 182 may have only a function ofsensing the degree of stretch of the lower substrate 110 without afunction of transmitting a data signal. The second connecting lines 182,particularly, the stretch sensing line will be described in more detailwith reference to FIGS. 8 and 9 in association with a stretch sensingfunction that senses the degree of stretch of the lower substrate 110.

Referring to FIG. 1, the connecting lines 180 electrically connect thepads disposed on adjacent second substrates 112 of the plurality ofsecond substrates 112 and extend in a curved shape between the pads.That is, the first connecting lines 181 and the second connecting lines182 each may extend in a wavy shape. For example, as shown in FIG. 1,the first connecting lines 181 and the second connecting lines 182 mayhave a sine waveform. However, the shapes of the first connecting lines181 and the second connecting lines 182 are not limited thereto. Forexample, the first connecting lines 181 and the second connecting lines182 may have various shapes, for example, they may extend in a zigzagshape or a plurality of diamond-shaped connecting lines extend with theapexes connected.

The first connecting lines 181 and the second connecting lines 182, forexample, may be made of a metal material such as copper (Cu), silver(Ag), gold (Au). Accordingly, since the connecting lines 180 have acurved shape, even though the connecting lines 180 are made of a metalmaterial, the stretchable display device 1000 of the present disclosuremay minimize damage to the connecting lines 180 when the display panel100 is stretched.

The lower substrate 110 may include a plurality of pixel areas PAdefining unit cells, an active area AA including the plurality of pixelareas PA, and a non-active area NA surrounding the active area AA.

The plurality of pixel areas PA each may be an area defining a unit cellof the stretchable display device 1000. Each pixel area PA may bedefined in an area where one second substrate 112 is disposed on thefirst substrate 111. That is, the pixel area PA may be defined as anarea including one second substrate 112 and the first substrate 111surrounding the second substrate 112. Alternatively, the pixel area PAmay be defined as an area defined by a middle line in the firstdirection X and a middle line in the second direction Y in the spacingarea between adjacent second substrates 112 in accordance with the shapeof the second substrates 112. A light emitting element and variousdriving elements for driving the light emitting element, for example, aswitching thin film transistor, a driving thin film transistor, acapacitor, etc. are disposed on the second substrates 112 in the pixelarea PA.

The active area AA is an area where images are displayed in thestretchable display device 1000. The active area AA includes theplurality of pixel areas PA and the spaces between the pixels. That is,the plurality of pixel areas PA may be disposed in a checkerboard shapein the active area AA. The plurality of second substrates 112 aredisposed in the active area AA on the first substrate 111 and are spacedapart from each other with gaps of a first selected distance betweenthem.

The non-active area NA is an area adjacent to the active area AA. Thereare no light emitting elements in the NA. The non-active area NA may bedisposed to surround the active area AA, adjacent to the active area AA.The non-active area NA is an area where an image is not displayed, andlines and circuits may be disposed in the non-active area NA. Forexample, a driving circuit such as a gate driving unit and a datadriving unit, and a plurality of signal pads and power pads may bedisposed in the non-active area AA. The driving circuit and each of thepads may be connected to each of the plurality of pixels disposed in theactive area AA. The plurality of second substrates 112 made a materialthat is more rigid than the first substrate 111 may be spaced anddisposed with predetermined gaps in the non-active area NA, equally tothe active area AA, on the first substrate 111 made of a bendable orstretchable material.

When the first substrate 111 is stretched, the second substrates move asecond distance apart from each other that is greater than the firstselected distance. The connecting lines 180 provide electricalconnection between the second substrates when they are the firstdistance apart from each other. When the first substrate 111 isstretched and the second substrates move a greater distance apart fromeach other, the connecting lines also stretch maintaining the electricalconnections between the respective second substrates 112 to each other.

Although the plurality of second substrates 112 is described as beingspaced apart from each other and disposed in the non-active area NA,equally to the active area AA, and being on the first substrate 111 withreference to FIG. 1 in one embodiment, the present disclosure is notlimited thereto. The NA might have one or two larger substrates that arepositioned directly adjacent to each other and the display be designedin such a way that the NA is not flexible to stretchable. Substratesmade of the same material as the second substrates may be disposed inthe non-active area NA throughout the entire surface of the firstsubstrate 111. As described above, the reason of disposing the pluralityof second substrates 112 or disposing substrates made of the samematerial as the second substrates on the first substrate 111 is forreducing damage to the driving unit or the pads disposed in thenon-active area NA. Accordingly, in the structure in which the pluralityof second substrates 112 are spaced and disposed in the non-active areaNA, driving elements that may drive a plurality of subpixels, forexample, transistors or IC chips constituting a gate driving unit or adata driving unit may be disposed on each of the plurality of secondsubstrates 112. The connecting lines 180 in the active area AA mayelectrically connect the second substrates 112 in the non-active area NAand the second substrates 112 in the active area AA to each other byextending.

The flexible connecting film 200, which is films disposed with variouscomponents on a base film 210 made of a flexible material, is acomponent for supplying signals to the plurality of pixels disposed inthe active area A/A of the lower substrate 110. The flexible connectingfilm 200 is disposed between the display panel 100 and the printedcircuit board 300 and transmits signals input from the printed circuitboard 300 to the pixels disposed in the active area AA of the lowersubstrate 110. That is, the flexible connecting film 200 may be disposedbetween the lower substrate 110 of the display panel 100 and the printedcircuit board 300 and may electrically connect the lower substrate 110and the printed circuit board 300.

The flexible connecting film 200 may be bonded by a plurality of bondingpads disposed in the non-active area NA. As shown in FIG. 1, a pluralityof flexible connecting films 200 may be disposed in the non-active areaNA. At least one of the plurality of flexible connecting films 200 mayperform a function that supplies a power voltage, a data voltage, etc.to each of the plurality of pixels disposed in the active area AAthrough the bonding pads. Further, at least another one of the pluralityof flexible connecting films 200 may also perform a function thatcalculates the degree of stretch by receiving a stretch sensing signalfrom connecting lines 180, which perform a function that senses thedegree of stretch, of the plurality of connecting lines 180 disposed onthe display panel 100 through the bonding pads.

The flexible connecting films 200 include a base film 210 and a drivingIC 220 and various other components may be disposed on the flexibleconnecting films 200.

The base film 210 is a layer supporting the driving IC 220. The basefilm 210 may be made of an insulating material, and more detail, thebase film 210 may be made of an insulating material having flexibilitysuch as polyimide (PI).

The driving IC 220 is a component that is disposed on the base film 210and processes data for displaying images and driving signals forprocessing the data. Further, the driving ICs 220 connected to thestretch sensing lines may sense the degree of stretch of the lowersubstrate 110 and transmit a sensed stretch value to the controller, forexample, a timing controller disposed on the printed circuit board 300through the stretch sensing lines. Although the driving ICs 220 areshown as being mounted in a COF type in FIG. 1, the driving ICs 220 arenot limited thereto and may be mounted in the type of Chip On Glass(COG) or Tape Carrier Package (TCP).

Controllers such as an IC chip and a circuit, for example, a timingcontroller may be mounted on the printed circuit board 300. In oneembodiment, the printed circuit board 300 is rigid and does not stretch.Further, a memory, a processor, etc. also may be mounted on the printedcircuit board 300. The printed circuit board 300 transmits signals fordriving pixels from the controllers to the pixels. The printed circuitboard 300 may create compensation data by comparing the stretch sensingvalue transmitted from the driving ICs 220 connected to the stretchsensing lines with a predetermined reference value.

The printed circuit board 300 may be electrically connected to each ofthe plurality of pixels disposed in the active area AA of the displaypanel 100 by being connected to the flexible connecting films 200.

The upper substrate 120 is a substrate overlapped with the lowersubstrate 110 to protect various components of the stretchable displaydevice 1000. The upper substrate 120, which is a flexible substrate, maybe made of a bendable, pliant or stretchable insulating material. Forexample, the upper substrate 120 may be made of a bendable, pliant orstretchable material and may be made of the same material as the firstsubstrate 111 of the lower substrate 110, but is not limited thereto.

Though not shown in FIG. 1, the stretchable display device 1000according to an embodiment of the present disclosure may further includea polarizing layer. The polarizing layer, which is a configurationsuppressing external light reflection by the stretchable display device1000, may be disposed on the upper substrate 120 while overlapping theupper substrate 120. However, the polarizing layer is not limitedthereto and, may be disposed under the upper substrate 120, may bedisposed under the lower substrate 110, or may be omitted, depending onthe configuration of the stretchable display device 1000.

FIGS. 2 to 5 are referred to hereafter to describe in more detail thestretchable display device 1000 according to an embodiment of thepresent disclosure.

FIG. 2 is an enlarged plan view enlarging one pixel area disposed in astretchable display device according to an embodiment of the presentdisclosure. FIG. 3 is a schematic cross-sectional view of one subpixelof a stretchable display device according to an embodiment of thepresent disclosure. FIG. 4 is a schematic cross-sectional view of onesubpixel of a stretchable display device according to another embodimentof the present disclosure. FIG. 5 is a schematic cross-sectional viewtaken along line V-V of FIG. 2.

First, referring to FIG. 2, a first substrate 111 made of a pliablematerial and a second substrate 112 made of a material that is morerigid than the first substrate 111 and disposed on the first substrate111 are disposed in a pixel area PA of the stretchable display device1000 according to an embodiment of the present disclosure.

A pixel PX including a light emitting element is disposed on the secondsubstrate 112 in the pixel area PA and a plurality of connecting lines180 connecting pixels PX disposed in a plurality of second substrates112 to each other is disposed on the first substrate 111.

The pixels PX emit light having a specific wavelength band. For example,the pixels PX include sub-pixels SPX respectively emitting red, green,and blue light. Although three subpixels SPX emitting red, green, andblue light are described in an embodiment of the present disclosure, thepresent disclosure is not limited thereto. For example, the pixels PXmay further include a subpixel emitting white light other than thesubpixels SPX emitting red, green, and blue light. When a subpixelemitting white light is included, the stretchable display device 1000according to an embodiment of the present disclosure may further includea color filter. The subpixels SPX each may include a thin filmtransistor and a light emitting element. The light emitting element maybe any one of an organic light emitting element and a micro LED.

Referring to FIG. 3 to describe the structure of the subpixels SPX inmore detail, a second substrate 112 on which a thin film transistor 150and a light emitting element 160 are disposed is disposed in apredetermined area of the first substrate 111 of the lower substrate110. As described above, the area where the second substrate 112 onwhich the thin film transistor 150 and the light emitting element 160are disposed is disposed may be referred to as a rigid area RA and theareas where a first connecting line 181 and a second connecting line 182are disposed may be referred to as pliable areas SA.

Referring to FIG. 3, a buffer layer 113 is disposed on the secondsubstrate 112 of the rigid area RA. The buffer layer 113 may be made ofan insulating material, and for example, may be made as a singleinorganic layer or a multi-inorganic layer made of a silicon nitride(SiNx), a silicon oxide (SiOx), or silicon oxynitride (SiON).

The buffer layer 113 is disposed in an area overlapped with the secondsubstrate 112 of the rigid area RA to protect various components of thestretchable display device 1000 against permeation of water, oxygen,etc. from the outside. This is because the buffer layer 113 may be madeof an inorganic material, so they may be easily damaged, such ascracking, when the stretchable display device 1000 is stretched.Accordingly, the buffer layer 113 may be formed over the secondsubstrate 112 of the rigid area RA by patterning similar to the shape ofthe second substrate 112 of the rigid area RA without being formed tothe pliable areas SA that are the spacing area between a plurality ofsecond substrates 112. Therefore, since the buffer layer 113 is formedin the area overlapped with the second substrate 112 of the rigid areaRA, it is possible to suppress damage to the buffer layer 113 eventhough the stretchable display device 1000 according to an embodiment ofthe present disclosure is deformed, such as, bending or stretching.However, the buffer layer 113 may be omitted, depending on the structureor characteristics of the stretchable display device 1000.

Referring to FIG. 3, a transistor 150 including a gate electrode 151, anactive layer 152, a source electrode 153, and a drain electrode 154 isformed on the buffer layer 113. For example, as for the process offorming the transistor 150, the active layer 152 is formed on the bufferlayer 113, and a gate insulating layer 114 for insulating the activelayer 152 and the gate electrode 152 from each other is formed on theactive layer 152. An inter-layer insulating layer 115 is formed toinsulate the gate electrode 151, the source electrode 153, and the drainelectrode 154 from each other, and the source electrode 153 and thedrain electrode 154 that are in contact with the active layer 152 areformed on the inter-layer insulating layer 115.

The gate insulating layer 114 and the inter-layer insulating layer 115may be formed in the area overlapped with the second substrate 112 inthe rigid region RA by patterning. The gate insulating layer 114 and theinter-layer insulating layer 115 may also be made of an inorganicmaterial, equally to the buffer layer 113, so they may be easily damagedsuch as cracking when the stretchable display device 1000 is stretched.Accordingly, the gate insulating layer 114 and the inter-layerinsulating layer 115 may be formed over the second substrate 112 of therigid area RA by patterning similarly to the shape of the secondsubstrate 112 of the rigid area RA without being formed in the areasbetween the second substrates 112 on which the thin film transistors 150are disposed, that is, the pliable areas SA.

Only a driving thin film transistor of various thin film transistorsthat may be included in the stretchable display device 1000 is shown inFIG. 3 for the convenience of description, but a switching thin filmtransistor, a capacitor, etc. may be included in the display device.Further, although the thin film transistor 150 is described as having acoplanar structure in the present disclosure, it is not limited theretovarious transistors, for example, having a staggered structure may beused.

Referring to FIG. 3, a gate pad 141 is disposed on the gate insulatinglayer 114. The gate pad 141 is a pad for transmitting a gate signal to aplurality of subpixels SPX. The gate pad 141 may be made of the samematerial as the gate electrode 151, but is not limited thereto.

Referring to FIG. 3, a planarization layer 116 is formed on the thinfilm transistor 150 and the inter-layer insulating layer 115. Theplanarization layer 116 planarizes the top of the thin film transistor150. The planarization layer 116 may be composed of a single layer or aplurality of layers and may be made of an organic material. For example,the planarization layer 116 may be made of an acrylic-based organicmaterial, but is not limited thereto. The planarization layer 116 mayhave a contact hole for electrically connecting the thin film transistor150 and a first electrode 161 of the organic light emitting element 160,a contact hole for electrically connecting a data pad 143 and the sourceelectrode 153, and a contact hole for electrically connecting aconnecting pad 142 and a gate pad 141.

In some embodiments, a passivation layer may be formed between the thinfilm transistor 150 and the planarization layer 116. That is, apassivation layer covering the thin film transistor 150 may be formed toprotect the thin film transistor 150 from permeation of water, oxygen,etc. The passivation layer may be made of an inorganic material and maybe composed of a single layer or a multi-layer, but is not limitedthereto.

Referring to FIG. 3, the data pad 143, the connecting pad 142, and theorganic light emitting element 160 are disposed on the planarizationlayer 116.

The data pad 143 may transmit a data signal from a second connectingline 182, which functions as a data line, to a plurality of subpixelsSPX. The data pad 143 is connected to the source electrode 153 of thethin film transistor 150 through a contact hole formed at theplanarization layer 116. The data pad 143 may be made of the samematerial as the first electrode 161 of the organic light emittingelement 160, but is not limited thereto. The data pad 143 may be made ofthe same material as the source electrode 153 and the drain electrode154 of the thin film transistor 150, not on the planarization layer 116,but on the inter-layer insulating layer 115.

The connecting pad 142 and the gate pad 141 may transmit a gate signalfrom a first connecting line 181, which functions as a gate line, to aplurality of subpixels SPX. The connecting pad 142 is connected to thegate pad 141 through contact holes formed at the planarization layer 116and the inter-layer insulating layer 115 and transmits a gate signal tothe gate pad 141. The connecting pad 142 may be made of the samematerial as the data pad 143, but is not limited thereto.

The organic light emitting element 160 includes the first electrode 161,an organic light emitting layer 162, and a second electrode 163. Indetail, the first electrode 161 is disposed on the planarization layer116. The first electrode 161 is an electrode configured to supply holesto the organic light emitting layer 162. The first electrode 161 may bemade of a transparent conductive material with a high work function. Thetransparent conductive material may include an Indium Tin Oxide (ITO),an Indium Zinc Oxide (IZO), and an Indium Tin Zinc Oxide (ITZO). Thefirst electrode 161 may be made of the same material as the data pad 143and the gate pad 141 disposed on the planarization layer 116, but is notlimited thereto. When the stretchable display device 1000 is implementedin a top emission type, the first electrode 161 may further include areflective plate. Further, the first electrode 161 may reflect lightemitted from the organic light emitting layer 162 and may be made ofmagnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag) which have alower work function than the second electrode 163, or an alloy thereof.

The first electrodes 161 are spaced and disposed respectively forsubpixels SPX and electrically connected to the thin film transistor 150though a contact hole of the polarization layer 116. For example,although the first electrode 161 is electrically connected to the drainelectrode 154 of the transistor 150 in FIG. 3, it may be electricallyconnected to the source electrode 153.

A bank 117 is formed on the first electrode 161, the data pad 143, theconnecting pad 142, and the planarization layer 116. The bank 117 is acomponent separating adjacent subpixels SPX. The bank 117 is disposed tocover at least partially both sides of adjacent first electrode 161,thereby partially exposing the tops of the first electrode 161. The bank117 may suppress the problem that an unexpected subpixel SPX emits lightor colors are mixed by light emitted in the lateral direction of thefirst electrode 161 due to concentration of a current on the edge of thefirst electrode 161. The bank 117 may be made of acrylic-based resin,benzocyclobutene (BCB)-based resin, or polyimide, but is not limitedthereto.

The bank 117 has a contact hole for connecting the second connectingline 182 and the data pad 143 and a contact hole for connecting thefirst connecting line 181 functioning as a gate line and the connectingpad 142.

The organic light emitting layer 162 is disposed on the first electrode161. The organic light emitting layer 162 is configured to emit light.The organic light emitting layer 162 may include a luminescent material,and the luminescent material may include a phosphorous material of afluorescent material, but is not limited thereto.

The organic light emitting layer 162 may be composed of one lightemitting layer. Alternatively, the organic light emitting layer 162 mayhave a stacked structure in which a plurality of light emitting layersis stacked with a charge generation layer therebetween. The organiclight emitting layer 162 may further include at least one organic layerof a whole transporting layer, an electron transporting layer, a holeblocking layer, an electron blocking layer, a hole injection layer, andan electron injection layer.

Referring to FIG. 3, the second electrode 163 is disposed on the organiclight emitting layer 162. The second electrode 163 supplies electrons tothe organic light emitting layer 162. The second electrode 163 may bemade of a material having a work function different from the material ofthe first electrode 161. The second electrode 163, for example, may bemade of Indium Tin Oxide (ITO)-based, Indium Zinc Oxide (IZO)-based,Indium Tin Zinc Oxide (ITZO)-based, Zinc Oxide (ZnO)-based, and TinOxide (TO)-based transparent conductive oxides or an Ytterbium (Yb)alloy. Alternatively, the second electrode 163 may be made of a metalmaterial.

Further, when the stretchable display device 1000 is implemented in atop emission type, the second electrode 163 may further include areflective plate.

Further, the second electrode 163 may reflect light emitted from theorganic light emitting layer 162 and may be made of magnesium (Mg),calcium (Ca), aluminum (Al), silver (Ag) which have a lower workfunction than the first electrode 161, or an alloy thereof. The secondelectrode 163 may be formed by patterning to overlap each of the secondsubstrates 112 of the rigid areas RA. That is, the second electrode 163is formed in the areas overlapped with the second substrates 112 of therigid areas RA and may be disposed not to be formed in the pliable areasSA. Since the second electrode 163 is made of a material, such as atransparent conductive oxide, a transparent metal material, a reflectivemetal material, and the like, when the second electrode 163 is formed inthe areas between second substrates 112 on which the organic lightemitting elements 160 are disposed, that is, is formed even in thepliable areas SA, the second electrode 163 may be damaged when thestretchable display device 1000 is stretched and contracted. The secondelectrode 163 may be formed to respectively correspond to the secondsubstrates 112 of the rigid areas RA in a plane. The second electrode163 may be formed to have an area not overlapped with the areas wherethe connecting lines 180 are formed of the areas overlapped with thesecond substrates 112 in the rigid areas RA.

Though not shown in FIG. 3, an insulating layer for insulation betweentwo sensing lines constituting the stretch sensing lines disposed byextending from the pliable area SA may be further disposed on theorganic light emitting element 160.

Referring to FIG. 3, an encapsulation layer 108 is disposed on theorganic light emitting element 160. The encapsulation layer 108 may sealthe organic light emitting element 160 by covering the organic lightemitting element 160 in contact with a portion of the top of the bank117. Accordingly, the encapsulation layer 108 protects the organic lightemitting element 160 from water, air, or physical shock that maypermeate from the outside.

The encapsulation layers 108 respectively cover the second electrode 163patterned to respectively overlap the second substrates 112 of the rigidareas RA and may be formed on the second substrates 112, respectively.That is, the encapsulation layers 108 are disposed to each cover onesecond electrode 163 on one second substrate 112 and the encapsulationlayer 108 disposed on each of the second substrates 112 of the rigidareas RA may be spaced apart from each other.

The encapsulation layer 108 may be formed in the areas overlapped withthe second substrates 112 of the rigid areas RA. As described above,since the encapsulation layers 108 may be configured to include aninorganic layer, they may be easily damaged, such as cracking, when thestretchable display device 1000 is stretched. In particular, since theorganic light emitting element 160 is vulnerable to water or oxygen,when the encapsulation layer 108 is damaged, reliability of the organiclight emitting element 160 may be reduced. Therefore, since theencapsulation layer 108 is not formed in the pliable areas SA, damage tothe encapsulation layer 108 may be minimized even though the stretchabledisplay device 1000 according to an embodiment of the present disclosureis deformed, such as, bending or stretching.

However, if necessary, the encapsulation layer 108 may be formed on thefront surface of the lower substrate 110 including the rigid areas RAand the pliable areas SA.

Compared with common flexible organic light emitting display devices ofthe related art, the stretchable display device 1000 according to anembodiment of the present disclosure has a structure in which theplurality of second substrates 112 that is relatively rigid is spacedapart from each other and disposed on the first substrate 111 that isrelatively pliable. The second electrode 163 and the encapsulationlayers 108 of the stretchable display device 1000 are disposed bypatterning to correspond to the plurality of second substrates 112,respectively. That is, the stretchable display device 1000 according toan embodiment of the present disclosure may have a structure thatenables the stretchable display device 1000 to be more easily deformedwhen a user stretches or bends the stretchable display device 1000 andmay have a structure that may minimize damage to the constitutingcomponents of the stretchable display device 1000 when the stretchabledisplay device 1000 is deformed.

The lower substrate 110 configured in this way may be bonded to theupper substrate 120 shown in FIG. 1 by an adhesive layer (not shown).

Meanwhile, although an organic light emitting element is exemplified asa light emitting element in FIG. 3, the light emitting elements of thestretchable display device 1000 may be micro LEDs. The structure of onesubpixel when the light emitting elements of the stretchable displaydevice 1000 according to an embodiment of the present disclosure aremicro LEDs is described hereafter.

Referring to FIG. 4, a common line CL is disposed on the gate insulatinglayer 114. The common line CL is a line applying a common voltage to aplurality of subpixels SPX. The common line CL may be made of the samematerial as the source electrode 153 and the drain electrode 154 of thethin film transistor 150, but is not limited thereto. For example, thecommon line CL may also be made of the same material as the gateelectrode 151 of the thin film transistor 150.

A reflective layer 423 is disposed on the inter-layer insulating layer115. The reflective layer 423 is a layer for discharging light, which isemitted to the first substrate 111 of light emitting from the micro LED410, to the outside by reflecting the light upward a stretchable displaydevice 1000. The reflective layer 423 may be made of a metal materialhaving high reflectance.

A first adhesive layer 417 is disposed on the reflective layer 423 tocover the reflective layer 423. The first adhesive layer 417, which is alayer for bonding the micro LED 410 on the reflective layer 423, mayinsulate the reflective layer 423 made of a metal material and the microLED 410 from each other. The first adhesive layer 417 may be made of athermosetting material or a photocuring material, but is not limitedthereto. Although the first adhesive layer 417 covers only thereflective layer 423 in FIG. 4, the disposition position of the firstadhesive layer 417 is not limited thereto.

The micro LED 410 is disposed on the first adhesive layer 417. The microLED 410 is disposed while overlapping the reflective layer 423. Themicro LED 410 includes an n-type layer 411, an active layer 412, ap-type layer 413, a p-electrode 414, and an n-electrode 415. The microLED 410 is described as a micro LED 410 of a lateral structurehereafter, but the structure of the micro LED 410 is not limitedthereto. For example, a micro LED of a flip chip structure may be usedas the micro LED 410.

In detail, the n-type layer 411 of the micro LED 410 is disposed whileoverlapping the reflective layer 423 on the first adhesive layer 417.The n-type layer 411 may be formed by injecting an n-type impurity intoa gallium nitride having excellent crystallinity. The active layer 412is disposed on the n-type layer 411. The active layer 412, which is alight emitting layer that emits light in the micro LED 410, may be madeof a nitride semiconductor, for example, an indium gallium nitride. Thep-type layer 413 is disposed on the active layer 412. The p-type layer413 may be formed by injecting a p-type impurity into a gallium nitride.However, the configuration materials of the n-type layer 411, the activelayer 412, and the p-type layer 413 are not limited thereto.

The p-electrode 414 is disposed on the p-type layer 413 of the micro LED410. The n-electrode 415 is disposed on the n-type layer 411 of themicro LED 410. The n-electrode 415 is spaced and disposed apart from thep-electrode 414. In detail, the micro LED 410 may be manufactured bysequentially stacking the n-type layer 411, the active layer 412, andthe p-type layer 413, etching a predetermined portion of the activelayer 412 and the p-type layer 413, and then forming the n-electrode 415and the p-electrode 414. In some embodiments, the predetermined portionis a space for spacing the n-electrode 415 and the p-electrode 414 andthe predetermined portion may be etched to expose a portion of then-type layer 411. In other words, the surface of the micro LED 410 wherethe n-electrode 415 and the p-electrode 415 are disposed is not aplanarized surface and may have different levels. Accordingly, thep-electrode 414 is disposed on the p-type layer 413, the n-electrode 415is disposed on the n-type layer 411, and the p-electrode 414 and then-electrode 415 are spaced and disposed apart from each other atdifferent levels. Therefore, the n-electrode 415 may be disposed moreadjacent to the reflective layer 423 in comparison to the p-electrode414. The n-electrode 415 and p-electrode 414 may be made of a conductivematerial, for example, a transparent conductive oxide. Alternatively,the n-electrode 415 and p-electrode 414 may be made of the samematerial, but are not limited thereto.

A planarization layer 116 is disposed on the inter-layer insulatinglayer 114 and the first adhesive layer 417. The planarization layer 116is a layer that planarizes the top of the thin film transistor 150. Theplanarization layer 116 may be disposed to planarize the top of theplanarization layer 116 in an area excepting the area where the microLED 410 is disposed. The planarization layer 116 may be composed of twoor more layers.

A first electrode 421 and a second electrode 422 are disposed on theplanarization layer 116. The first electrode 421 is an electrode thatelectrically connects the thin film transistor 150 and the micro LED410. The first electrode 421 is connected to the p-electrode 414 of themicro LED 410 through a contact hole formed at the planarization layer116. The first electrode 421 is connected to the drain electrode 154 ofthe thin film transistor 150 through contact holes formed at theplanarization layer 116 and the inter-layer insulating layer 115.However, the first electrode 421 is not limited thereto and may beconnected to the source electrode 153 of the thin film transistor 150,depending on the type of the thin film transistor 150. The p-electrode414 of the micro LED 410 and the drain electrode 154 of the thin filmtransistor 150 may be electrically connected by the first electrode 421.

The second electrode 422 is an electrode that electrically connects themicro LED 410 and the common line CL. In detail, the second electrode422 is connected to the common line CL through contact holes formed atthe planarization layer 116 and the inter-layer insulating layer 115 andis connected to the n-electrode 415 of the micro LED 410 through acontact hole formed at the planarization layer 116. Accordingly, thecommon line CL and the n-electrode 415 of the micro LED 410 areelectrically connected.

When the stretchable display device 1000 is turned on, voltages havingdifferent levels may be supplied respectively to the drain electrode 154of the thin film transistor 150 and the common line CL. The voltage thatis applied to the drain electrode 154 of the thin film transistor 150may be applied to the first electrode 421 and a common voltage may beapplied to the second electrode 422. Voltages having different levelsmay be applied to the p-electrode 414 and the n-electrode 415 throughthe first electrode 421 and the second electrode 422, so the micro LED410 may emit light.

Although the thin film transistor 150 is described as being electricallyconnected to the p-electrode 414 and the common line CL is described asbeing electrically connected to the n-electrode 415 in FIG. 4, they arenot limited thereto. That is, the thin film transistor 150 may beelectrically connected to the n-electrode 415 and the common line CL maybe electrically connected to the p-electrode 414.

A bank 117 is disposed on the planarization layer 116, the firstelectrode 421, the second electrode 422, the data pad 143, and theconnecting pad 142. The bank 117 may be disposed to overlap an end ofthe reflective layer 423 and a portion not overlapped with the bank 117of the reflective layer 423 may be defined as a light emitting area. Thebank 117 may be made of an organic insulating material and may be madeof the same material as the planarization layer 116. The bank 117 may beconfigured to include a black material to suppress a color mixingphenomenon due to light emitted from the micro LED 410 and transmittedto an adjacent subpixel SPX.

As described above, the light emitting elements of the stretchabledisplay device 1000 according to an embodiment of the present disclosuremay be organic light emitting elements, but also may be micro LEDs 410.Since the micro LED 410 is made of not an organic material, but aninorganic material, reliability is excellent, so the lifespan is longerthan that of a liquid crystal light emitting element or an organic lightemitting element. The micro LED 410 has a quick turning speed, has smallpower consumption, has excellent stability because it has strongshock-resistance, and may display high-luminance images because it hasexcellent emission efficiency. Accordingly, the micro LED 410 is anelement that is suitable to be applied even to very large screens. Inparticular, since the micro LED 410 is made of not an organic material,but an inorganic material, an encapsulation layer that is required whenan organic light emitting element is used may not be used. Accordingly,the encapsulation layer that may be easily damaged, such as cracking,when the stretchable display device 1000 is stretched may be omitted.Accordingly, it is possible to omit use of an encapsulation layer thatmay be damaged when the stretchable display device 1000 according toanother embodiment of the present disclosure is deformed such as bendingor stretching, by using the micro LED 410 as a light emitting element inthe stretchable display device 1000. Further, since the micro LED 410 ismade of not an organic material, but an inorganic material, the emittingelements of the stretchable display device 1000 according to anotherembodiment of the present disclosure may be protected from water oroxygen and their reliability may be excellent.

Meanwhile, referring to FIGS. 3 and 4, the first connecting line 181 andthe second connecting line 182 each are connected to the gate pad 141and the connecting pad 142 or the data pad 143 disposed on the secondsubstrate 112 of the rigid area RA and may be extended and disposed tothe pliable areas SA. In some embodiments, a line damage suppressionlayer 112S may be disposed under the first connecting line 181 and thesecond connecting line 182 disposed on the pliable areas SA.

The line damage suppression layer 112S may be disposed on the firstsubstrate 111 in correspondence to the shape of the first connectingline 181 and the second connecting line 182 disposed on the pliableareas SA. That is, when the first connecting line 181 and the secondconnecting line 182 have a wavy shape, the line damage suppression layer112S may correspondingly have a wavy shape, and when the firstconnecting line 181 and the second connecting line 182 have a straightshape, the line damage suppression layer 112S may correspondingly have astraight shape. For example, the shape of the line damage suppressionlayer 112S formed on the first substrate 111 may substantially followthe shape of the first connecting line 181 and the second connectingline 182. The line damage suppression layer 112S may be made of the samematerial as the second substrate 112 disposed in the rigid area RA. Theline damage suppression layer 112S, for example, may include siliconrubber such as polydimethylsiloxane (PDMS), an elastomer such aspolyurethane (PU), styrene butadiene styrene (SBS), etc. Accordingly, bydisposing the line damage suppression layer 112S under the connectingline 180 disposed in the pliable areas SA in the stretchable displaydevice 1000 according to an embodiment of the present disclosure, it ispossible to suppress damage to the connecting line 180 and controloverstretching of the lower substrate 110 when the stretchable displaydevice 1000 is stretched.

Referring to FIGS. 2 and 3, a plurality of connecting lines 180 forelectrically connecting a second substrate 112 and another secondsubstrate 112 disposed adjacent to the second substrate 112 are disposedon the first substrate 111. The plurality of connecting lines 180include a plurality of first connecting lines 181 disposed in the firstdirection X and a plurality of second connecting lines 182 disposed inthe second direction Y.

The plurality of first connecting lines 181 each may be electricallyconnected to a gate line 131 a, a high-potential power line 131 b, and alow-potential power line 131 c disposed on the second substrate 112. Theplurality of first connecting lines 181 may have a curved shape, thatis, a wavy shape to correspond to stretching of the lower substrate 110.For example, a curved shape means wave shape or a diamond shape. Theplurality of first connecting lines 181, for example, may be made of ametal material such as copper (Cu), silver (Ag), and gold (Au).Accordingly, even though the first connecting lines 181 are made of ametal material, the first connecting lines 181 extend to have a curvedshape on the first substrate 111, whereby damage to the plurality offirst connecting lines 181 may be minimized even though the stretchabledisplay device 1000 is stretched.

The plurality of second connecting lines 182 each may be electricallyconnected to first to third data lines 132 a, 132 b, and 132 c disposedon the second substrate 112. The plurality of second connecting lines182 may have a curved shape, that is, a wavy shape to correspond tostretching of the lower substrate 110. The plurality of secondconnecting lines 182, for example, may be made of a metal material suchas copper (Cu), silver (Ag), and gold (Au). Accordingly, even though theplurality of second connecting lines 182 is made of a metal material,the second connecting lines 182 extend to have a curved shape on thefirst substrate 111, whereby damage to the second connecting lines 182may be minimized even though the stretchable display device 1000 isstretched.

Any one second connecting line 182S (hereafter, referred to as a ‘secondstretch sensing line’) of the plurality of second connecting lines 182may sense the degree of stretch of the lower substrate 110 whileperforming a function that transmits a data signal. Accordingly, thesecond stretch sensing line 182S may be electrically connected to firstand second data lines 132 a and 132 b disposed on the second substrate112.

The second stretch sensing line 182S may include a second stretchsensing Rx line 182Sa (which may be referred as an Rx line) and a secondstretch sensing Tx line 182Sb that may sense the degree of stretch.Accordingly, the second stretch sensing Rx line 182Sa and the secondstretch sensing Tx line 182Sb that are configured to be able to sensethe degree of stretch of the lower substrate 110 are disposed in thesecond stretch sensing line 182S that is any one connecting line of theplurality of connecting lines 180 in the stretchable display device 1000according to an embodiment of the present disclosure. Therefore, it ispossible to find out the degree of stretch of the lower substrate 110 bysensing capacitance C between the second stretch sensing Rx line 182Saand the second stretch sensing Tx line 182Sb before stretching andbetween the second stretch sensing Rx line 182Sa and the second stretchsensing Tx line 182Sb after stretching and determining a difference ofthe capacitance C before and after stretching.

Referring to FIG. 2, a gate line 131 a for transmitting a gate signal toeach subpixel SPX, a high-potential power line 131 b for transmittinghigh-potential power to each subpixel SPX, a low-potential power line131 c for transmitting low-potential power to each subpixel SPX, andfirst to third data lines 132 a, 132 b, and 132 c for transmitting adata signal to each subpixel SPX are disposed on the second substrate112.

The gate line 131 a, the high-potential power line 131 b, andlow-potential power line 131 c are disposed in the first direction X onthe second substrate 112 and may be electrically connected to aplurality of first connecting lines 181 disposed in the first directionX on the first substrate 111.

The first to third data lines 132 a, 132 b, and 132 c are disposed inthe second direction Y on the second substrate 112 and may beelectrically connected to a plurality of second connecting lines 182disposed in the second direction Y on the first substrate 111. Inparticular, the first data line 132 a may be electrically connected tothe second stretch sensing Rx line 182Sa extending from the secondstretch sensing line 182S disposed on the first substrate 111. Thesecond data line 132 b may be electrically connected to the secondstretch sensing Tx line 182Sb extending from the second stretch sensingline 182S disposed on the first substrate 111. Accordingly, the secondstretch sensing Rx line 182Sa may be the first data line 132 a on thesecond substrate 112 and the second stretch sensing Tx line 182Sb may bethe second data line 132 b on the second substrate 112. In someembodiments, the first data line 132 a is a line supplying a data signalto any one subpixel SPX and the second data line 132 b is a linesupplying a data signal to another subpixel SPX disposed adjacent to theany one subpixel SPX. That is, the second stretch sensing Rx line 182Saand the second stretch sensing Tx line 182Sb constituting the secondstretch sensing line 182S on the first substrate 111 may sense thedegree of stretch according to stretch of the first substrate 111. Thesecond stretch sensing Rx line 182Sa and the second stretch sensing Txline 182Sb constituting the second stretch sensing line 182S on thesecond substrate 112 may transmit a data signal. Further, the secondstretch sensing Rx line 182Sa and the second stretch sensing Tx line182Sb constituting the second stretch sensing line 182S each function asa data line supplying data to two subpixels, whereby it is possible toincrease area utilization by reducing the number of connecting linesdisposed on the first substrate 111.

Referring to FIG. 5, the second stretch sensing Rx line 182Sa of thesecond stretch sensing line 182S disposed on the first substrate 111 iselectrically connected to the first data line 132 a transmitting a datasignal to a corresponding subpixel by the data pad 143. Further, thesecond stretch sensing Tx line 182Sb of the second stretch sensing line182S disposed on the first substrate 111 is electrically connected tothe second data line 132 b of a subpixel adjacent to the subpixelconnected to the first data line 132 a. Accordingly, the second stretchsensing Rx line 182Sa of the second stretch sensing line 182S maytransmit a data signal to any one subpixel and the second stretchsensing Tx line 182Sb may transmit a data signal to a subpixel adjacentto the any one subpixel.

As such, when the second stretch sensing line 182S plays both roles as adata line and stretch sensing line, the second stretch sensing line 182Smay be configured to transmit a data signal in a period in which a datasignal is applied, and senses the degree of stretch of the firstsubstrate 111 in a period in which a data signal is not applied.

Such a stretchable display device 1000 according to an embodiment of thepresent disclosure is configured such that any one second connectingline 182S of the plurality of connecting lines 180, particularly, theplurality of second connecting lines 182 includes the second stretchsensing Rx line 182Sa and the second stretch sensing Tx line 182Sb.Accordingly, when the first substrate 111 is stretched, the degree ofstretch is sensed using the capacitance between the second stretchsensing Rx line 182Sa and the second stretch sensing Tx line 182Sb.Further, by connecting each of the second stretch sensing Rx line 182Saand the second stretch sensing Tx line 182Sb to each of the first dataline 132 a and the second data line 132 b disposed on the secondsubstrate 112, it is possible to reduce the area of the secondconnecting line 182S disposed on the first substrate 111.

Meanwhile, as described above, the case when at least one connectingline 182S of the plurality of connecting lines 180 may transmit a datasignal to a subpixel SPX and sense the degree of stretch of the firstsubstrate 111 is described as an embodiment. However, the stretchabledisplay device 1000 according to an embodiment of the present disclosureis not limited thereto and may be configured to be able to transmit agate signal and play a role that may sense the degree of stretch of thefirst substrate 111. As such, an embodiment about a stretch sensing linethat plays roles as a gate line and stretch sensing is described next inmore detail with reference to FIGS. 6 and 7.

FIG. 6 is an enlarged plan view enlarging one pixel area disposed in astretchable display device according to another embodiment of thepresent disclosure. FIG. 7 is a schematic cross-sectional view takenalong line VII-VII′ of FIG. 6.

Before looking into FIGS. 6 and 7, the structure of one subpixel shownin FIGS. 6 and 7, as compared with the subpixel structure shown in FIGS.2 and 5, is different only in the disposition position of the stretchsensing line and is the same in substantial configuration, so repeateddescription for the same reference numerals is omitted.

First, referring to FIG. 6, a first stretch sensing line 181S of aplurality of connecting lines 180 disposed on a first substrate 111 maybe disposed to extend in a first direction X. That is, at least any oneof a plurality of first connecting lines 181 extending in the firstdirection X may be the first stretch sensing line 181S.

The first stretch sensing line 181S may include a first stretch sensingRx line 181Sa (which may be referred as an Rx line) and a first stretchsensing Tx line 181Sb that may sense the degree of stretch.

Referring to FIG. 6, first and second gate lines 131 a and 131 b fortransmitting a gate signal to each subpixel SPX, a high-potential powerline 131 c for transmitting high-potential power to each subpixel SPX, alow-potential power line 131 d for transmitting low-potential power toeach subpixel SPX, and first to third data lines 132 a, 132 b, and 132 cfor transmitting a data signal to each subpixel SPX are disposed on asecond substrate 112. Here, the first and second gate lines 131 a and131 b may be lines respectively transmitting a first scan signal and asecond scan signal in accordance with each subpixel.

Referring to FIG. 6, the first stretch sensing line 181S disposed on thefirst substrate 111 is disposed on the first gate line 131 a, and anyone of a first stretch sensing Rx line 181Sa and a first stretch sensingTx line 181Sb constituting the first stretch sensing line 181S may beelectrically connected to the first gate line 131 a.

Referring to FIG. 7, the first stretch sensing Rx line 181Sa of thefirst stretch sensing line 181S disposed on the first substrate 111 iselectrically connected to the first gate line 131 a transmitting a firstgate signal to each subpixel through a connecting pad 142. Accordingly,the first connecting line 181S including the first stretch sensing Rxline 181Sa may play a role of a gate line transmitting the first gatesignal. Further, the first stretch sensing Tx line 181Sb of the firststretch sensing line 181S disposed on the first substrate 111 may bedisposed on an insulating layer 118 positioned at a higher level thanthe first stretch sensing Rx line 181Sa. That is, the first stretchsensing Rx line 181Sa and the first stretch sensing Tx line 181Sb may bedisposed at different levels. An insulating layer may be interposedbetween the first stretch sensing Rx line 181Sa and the first stretchsensing Tx line 181Sb. In some embodiments, the insulating layer 118 maybe an inorganic layer that is a partial configuration of anencapsulation layer 108 of a subpixel.

As such, the first stretch sensing line 181S including the first stretchsensing Rx line 181Sa and the first stretch sensing Tx line 181Sb thatmay sense the degree of stretch by a capacitance difference before andafter stretching is disposed in the first direction X that is the sameas the direction in which a gate line extends in the stretchable displaydevice according to an embodiment of the present disclosure.Accordingly, it is possible to sense the degree of stretch in the firstdirection X by comparing the capacitance values between the firststretch sensing Rx line 181Sa and the first stretch sensing Tx line181Sb before and after stretching when the first substrate 111 isstretched in the first direction X.

Meanwhile, the first gate line 131 a and the first stretch sensing Rxline 181Sa of the first stretch sensing line 181S are described as beingelectrically connected in FIG. 7. However, a first stretch sensing line181S may be additionally disposed in the first direction X to perform astretch sensing function separately from the gate line disposed on asecond substrate 112.

Further, a stretch sensing line may be separately disposed not only inthe first direction X, but also in the second direction Y.

As such, an embodiment when a stretch sensing line that may sensestretch is additionally disposed is described next in detail withreference to FIGS. 8 and 9.

FIG. 8 is an enlarged plan view enlarging one pixel area disposed in astretchable display device according to another embodiment of thepresent disclosure. FIG. 9 is a schematic cross-sectional view takenalong line VIII-VIII′ of FIG. 8.

Before looking into FIGS. 8 and 9, the structure of one subpixel shownin FIGS. 8 and 9, as compared with the subpixel structure shown in FIGS.2 and 5, is different only in the disposition position of the stretchsensing line and is the same in substantial configuration, so repeateddescription for the same reference numerals is omitted.

Referring to FIG. 8, a stretch sensing line 182S of a plurality ofconnecting lines 180 disposed on a first substrate 111 may be disposedto extend in a second direction Y. That is, at least any one of aplurality of second connecting lines 182 extending in the seconddirection Y may be a second stretch sensing line 182S.

The second stretch sensing line 182S may include a second stretchsensing Rx line 182Sa and a second stretch sensing Tx line 182Sb thatmay sense the degree of stretch.

Referring to FIG. 8, a gate line 131 a for transmitting a gate signal toeach subpixel SPX, a high-potential power line 131 b for transmittinghigh-potential power to each subpixel SPX, a low-potential power line131 c for transmitting low-potential power to each subpixel SPX, andfirst to third data lines 132 a, 132 b, and 132 c for transmitting adata signal to each subpixel SPX are disposed on the second substrate112. Here, the second stretch sensing Rx line 182Sa and the secondstretch sensing Tx line 182Sb constituting the second stretch sensingline 182S may be disposed on a separate layer regardless of the first tothird data lines 132 a, 132 b, and 132 c transmitting a data signal toeach subpixel SPX.

Referring to FIG. 9, the second stretch sensing Rx line 182Sa of thesecond stretch sensing line 182S disposed on the first substrate 111 maybe spaced and disposed apart from a second electrode 163 of an organiclight emitting element 160. Further, the second stretch sensing Tx line182Sb is disposed on the second stretch sensing Rx line 182Sa and aninsulating layer 118 may be disposed between the second stretch sensingRx line 182Sa and the second stretch sensing Tx line 182Sb. In someembodiments, the insulating layer 118 may be an inorganic layerconstituting an encapsulation layer (108 in FIG. 3). That is, the secondstretch sensing line 182S extending from the first substrate 111 to thesecond substrate 112 regardless of the first to third data lines 132 a,132 b, and 132 c is disposed on the second substrate 112 and may bedisposed regardless of lines transmitting a signal even on the secondsubstrate 112.

As such, the second stretch sensing line 182S including the secondstretch sensing Rx line 182Sa and the second stretch sensing Tx line182Sb that may sense the degree of stretch by a capacitance differencebefore and after stretching is disposed to extend the second direction Ythat is the same as the direction in which the first to third data lines132 a, 132 b, and 132 c extend in the stretchable display deviceaccording to an embodiment of the present disclosure. Accordingly, it ispossible to sense the degree of stretch in the second direction Y bycomparing the capacitance values between the second stretch sensing Rxline 182Sa and the second stretch sensing Tx line 182Sb before and afterstretching when the first substrate 111 is stretched in the seconddirection Y.

Meanwhile, in an embodiment of the present disclosure, the cases whenthe first stretch sensing line 181S disposed in the first direction Xand the second stretch sensing line 182S disposed in the seconddirection Y are described as different embodiments. However, the firststretch sensing line 181S disposed in the first direction X and thesecond stretch sensing line 182S disposed in the second direction Y tosense the degree of stretch in both directions may be disposed togetherin the same first substrate 111.

A more detailed description of the configuration of such stretch sensinglines according to an embodiment of the present disclosure is asfollows.

FIG. 10 is a schematic plan view for illustrating the configuration ofstretch sensing lines disposed in a stretchable display device accordingto an embodiment of the present disclosure. FIG. 11 is a cross-sectionalview schematically showing one configuration example taken along linea-a′ of FIG. 10. FIG. 12 is a cross-sectional view schematically showingone configuration example taken along line b-b′ of FIG. 10. FIG. 13 is across-sectional view schematically showing another configuration exampletaken along line a-a′ of FIG. 10. FIG. 14 is a cross-sectional viewschematically showing another configuration example taken along lineb-b′ of FIG. 10. FIG. 15 is a cross-sectional view schematically showinganother configuration example taken along line a-a′ of FIG. 10. FIG. 16is a cross-sectional view schematically showing another configurationexample taken along line b-b′ of FIG. 10.

Referring to FIG. 10, a stretch sensing line 180S disposed on a firstsubstrate 111 may include a stretch sensing Rx line 180Sa and a stretchsensing Tx line 180Sb. Here, the stretch sensing line 180S may include afirst stretch sensing line 181S and a second stretch sensing line 182S.Such a stretch sensing line 180S is disposed to have a wavy shape, forexample, a sine waveform, so the stretch sensing line 180S may have aplurality of bending points P. Hereafter, for helping understanddescription, a portion to a bending point that is adjacent in onedirection with respect to any one bending point P is referred to anddescribed as a first connecting portion 180S1 and a portion to a bendingpoint that is adjacent in another direction with respect to any onebending point P is referred to and described as a second connectingportion 180S2.

Referring to FIGS. 10 and 11, the stretch sensing Rx line 180Sa and thestretch sensing Tx line 180Sb constituting the stretch sensing line 180Smay be disposed in a stacked type. However, in the stretch sensing line180S, the stretch sensing Rx line 180Sa and the stretch sensing Tx line180Sb may be disposed to cross at the bending point P. This isconfigured to sense the degree of stretch of a lower substrate 110 bysensing a capacitance C2 difference between the stretch sensing Rx line180Sa and the stretch sensing Tx line 180Sb in the presentspecification. This is for sensing the capacitance C2 difference bydisposing a stretch sensing Tx line 180Sb at the first connectingportion 180S1 and a stretch sensing Rx line 180Sa at the secondconnecting line 180S2 to face each other. However, an embodiment of thepresent disclosure in which a stretch sensing Rx line 180Sa of the firstconnecting portion 180S1 and the stretch sensing Rx line 180Sa of thesecond connecting line 180S2 are disposed to face each other is justdescribed as an example, whereby it may be possible to sense the degreeof stretch by sensing a capacitance difference according to the distanceof them.

It may also be possible to sense a degree of stretch using theprinciples of a strain gauge in which the resistance of a wire, such asa copper wire, changes when it is either stretched or compressed. Thevarious lines 180 s, 181 s 182 s etc. can be comprised a copper oranother metal that has a known change in resistance based on a selectedstretch of the wire. In some embodiments, the flexibility of the display100 will be of an amount that a stain gauge type stretch sensor will beacceptable, while in other embodiments, the flexibility may be so greatthat curved, twisty or more flexible connections is preferred to be usedfor lines 180 s, 181 s, 182 s, etc.

Referring to FIGS. 11 and 12, an insulating layer 180Si is interposedbetween the stretch sensing Rx line 180Sa and the stretch sensing Txline 180Sb. Looking into in more detail, the stretch sensing line 180Smay include a line damage suppression layer 112S disposed on the firstsubstrate 111, a stretch sensing Rx line 180Sa disposed on the linedamage suppression layer 112S, an insulating layer 180Si disposed on thestretch sensing Rx line 180Sa, and a stretch sensing Tx line 180Sbdisposed on the insulating layer 180Si.

The line damage suppression layer 112S is disposed along the line shapeof the stretch sensing line 180S, thereby being able to suppress damageby stretching of the stretch sensing line 180S. In an embodiment, theline damage suppression layer may be disposed under the stretch sensingline in correspondence to the shape of the stretch sensing line. Thatis, when the stretch sensing line 180S has a wavy shape, the line damagesuppression layer 112S may correspondingly have a wavy shape, and whenthe stretch sensing line 180S has a straight shape, the line damagesuppression layer 112S may correspondingly have a straight shape. Forexample, the shape of the line damage suppression layer 112S maysubstantially follow the shape of the stretch sensing line 180S. Theline damage suppression layer 112S may be made of a material that ismore rigid than the first substrate 111 and may be made of polyimide(PI), polyacrylate, polyacetate, or the like.

A stretch sensing Rx line 180Sa and stretch sensing Tx line 180Sb may bemade of a flexible metal material. For example, the stretch sensing Rxline 180Sa and stretch sensing Tx line 180Sb may be made of a metalmaterial such as copper (Cu), silver (Ag), and gold (Au). However, theconfiguration of the stretch sensing Rx line 180Sa and stretch sensingTx line 180Sb is not limited thereto. For example, the stretch sensingRx line 180Sa and stretch sensing Tx line 180Sb may be made bydistributing conductive particles in a stretchable base material made ofa similar material as the first substrate 111.

The insulating layer 180Si may be made of an insulating material, andfor example, may be made as a single inorganic layer made of a siliconnitride (SiNx), a silicon oxide (SiOx), or silicon oxynitride (SiON).However, the material constituting the insulating layer 180Si is notlimited only to an inorganic material and may be made of even an organiclayer.

Referring to FIG. 11, the stretch sensing Rx line 180Sa and the stretchsensing Tx line 180Sb of the first connecting portion 180S1 are stacked,and spaced and disposed by a predetermined distance, and capacitancebetween the stretch sensing Rx line 180Sa and stretch sensing Tx line180Sb In some embodiments may be referred to as first capacitance C1.That is, the first capacitance C1 may be capacitance between the stretchsensing Rx line 180Sa and stretch sensing Tx line 180Sb at the firstconnecting portion 18051. Accordingly, the first capacitance C1 valuemay be a constant value.

Further, the stretch sensing Rx line 180Sa and the stretch sensing Txline 180Sb of the second connecting portion 180S2 are stacked, andspaced and disposed by a predetermined distance and capacitance betweenthe stretch sensing Rx line 180Sa and stretch sensing Tx line 180Sb Insome embodiments may be referred to as first capacitance C1. That is,the first capacitance C1 of the first connecting portion 180S1 and thefirst capacitance C1 of the second connecting portion 180S2 may have thesame value.

Meanwhile, referring to FIG. 11, the capacitance between the stretchsensing Tx line 180Sb of the first connecting portion 180S1 and thestretch sensing Rx line 180Sa of the second connection portion 180S2 maybe defined as second capacitance C2. Accordingly, the stretchabledisplay device 1000 according to an embodiment of the present disclosuremay sense the degree of stretch of a stretchable display device bysensing a change of the second capacitance C2.

Stretch sensing of the stretch sensing line 180S configured as such maybe made through the following expression.

$\begin{matrix}{{\Delta\; C\; 2} = {{{{Capacitance}\mspace{14mu}{before}\mspace{14mu}{stretch}\mspace{14mu}\left( {C\; 2} \right)} - {{Capacitance}\mspace{14mu}{after}\mspace{14mu}{stretch}\mspace{14mu}\left( {C\; 2^{\prime}} \right)}} = {{\frac{C\; 1C\; 2}{{C\; 1} + {C\; 2}} - \frac{C\; 1C\; 2^{\prime}}{{C\; 1} + {C\; 2^{\prime}}}} = {C\; 1\left( {\frac{C\; 2}{{C\; 1} + {C\; 2}} - \frac{C\; 2^{\prime}}{{C\; 1} + {C\; 2^{\prime}}}} \right)}}}} & \left\lbrack {{Expression}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In the above expression, C1 is the first capacitance between the stretchsensing Rx line 180Sa and stretch sensing Tx line 180Sb at the firstconnecting portion 180S1 and the second connecting portion 180S2, C2 isthe second capacitance between the stretch sensing Tx line 180Sb at thefirst connecting portion 180S1 and the stretch sensing Rx line 180Sa atthe second connecting portion 180S2 before stretching, and CT is thesecond capacitance between the stretch sensing Tx line 180Sb at thefirst connecting portion 180S1 and the stretch sensing Rx line 180Sa atthe second connecting portion 180S2 after stretching.

In stretch sensing of the stretch sensing line 180S configured as such,when the first capacitance C1 value is large in comparison to the secondcapacitance value C2, sensing by stretch may be easy. For example, whenthe values of the first capacitance C1 and second capacitance C2 are thesame, for example, assuming that the first capacitance C1 and secondcapacitance C2 values are each 2, a sensing value by stretch iscalculated as ⅓ when substituting this value into the [Expression 1] andcalculating (first embodiment). Meanwhile, when the first capacitancevalue of the first capacitance C1 is larger than the second capacitancevalue of the second capacitance C2, for example, assuming that the firstcapacitance C1 value is 6 and the second capacitance C2 value is 3, asensing value by stretch is calculated as ½ when substituting thesevalues into the [Expression 1] and calculating (second embodiment).Further, when the first capacitance value of the first capacitance C1 issmaller than the second capacitance value of the second capacitance C2,for example, assuming that the first capacitance C1 value is 1 and thesecond capacitance C2 value is 3, a sensing value by stretch iscalculated as 1/12 when substituting these values into the [Expression1] and calculating (third embodiment). As such, when the firstcapacitance C1 value is higher than the second capacitance C2 value, asensing value by the largest stretch is derived, so it is possible tofind out a sensing change by stretch of the first substrate 111 moreeasily than when the first capacitance C1 value is higher than thesecond capacitance C2 value.

As such, in order to more easily sense the degree of stretch of thefirst substrate 111, the higher the dielectric constant of theinsulating layer 180Si than the first substrate 111, the moreadvantageous it may be. Accordingly, the higher the dielectric constantof the insulating material making the insulating layer 180Si than theinsulating material making the first substrate 111, the moreadvantageous it may be in stretch sensing of the first substrate 111.

Further, in the stretch sensing line 180S, the smaller the distancebetween the stretch sensing Rx line 180Sa and the stretch sensing Txline 180Sb disposed on each of the first connecting portion 180S1 andthe second connecting portion 180S2 before stretching than the distancebetween the stretch sensing Tx line 180Sb of the first connectingportion 180S1 and the stretch sensing Rx line 180Sa of the secondconnecting portion 180S2, the more advantageous it may be in stretchsensing.

Meanwhile, looking into the configuration of the stretch sensing line180S at a bending point P with reference to FIG. 12, the stretch sensingRx line 180Sa and the stretch sensing Tx line 180Sb may be disposed in astacked type on the same vertical axis.

As such, in the stretch sensing line 180S, the configuration in whichthe stretch sensing Rx line 180Sa and stretch sensing Tx line 180Sb arestacked and the insulating layer 180Si is interposed between the stretchsensing Rx line 180Sa and the stretch sensing Tx line 180Sb may beapplied to the embodiment described with reference to FIGS. 2 and 5described above.

Meanwhile, the stretch sensing Rx line 180Sa and the stretch sensing Txline 180Sb constituting the stretch sensing line 180S are describedabove as being sequentially stacked with the insulating layer 180Sitherebetween, but the configuration of the stretch sensing line is notlimited thereto.

Referring to FIGS. 13 and 14, a stretch sensing line 180S according toanother embodiment may be configured such that a stretch sensing Rx line180Sa and a stretch sensing Tx line 180Sb are disposed in the same planeand an insulating layer 180Si is disposed only on the stretch sensing Rxline 180Sa. By simultaneously forming the stretch sensing Rx line 180Saand the stretch sensing Tx line 180Sb and then forming the insulatinglayer 180Si such that the insulating layer 180Si is disposed only on thestretch sensing Rx line 180Sa, it is possible to reduce process steps,as compared with the embodiment shown in FIGS. 10 and 11, so such astretch sensing line 180S according to another embodiment may be moreadvantageous in terms of process.

Further, referring to FIGS. 15 and 16, a stretch sensing line 180S maybe a structure in which a transparent conductive layer 180St is furtherdisposed in the structure of the stretch sensing line 180S shown inFIGS. 13 and 14. That is, referring to FIGS. 15 and 16, the transparentconductive layer 180St may be disposed to be in direct contact with theinsulating layer 180Si and the stretch sensing Tx line 180Sb. In someembodiments, a transparent metal layer 180St may be made of any one ofan Indium Tin Oxide (ITO), an Indium Zinc Oxide (IZO), and an Indium TinZinc Oxide (ITZO). As such, by disposing the transparent metal layer180St over the stretch sensing Rx line 180Sa and the stretch sensing Txline 180Sb and disposed to be in direct contact with any one of thestretch sensing Rx line 180Sa and the stretch sensing Tx line 180Sb,thereby being able optimizing touch sensitivity while increasing a firstcapacitance C1 value.

In order to sense the degree of stretch of such a first substrate 111, astretch sensing unit may be further disposed in the stretchable displaydevice 1000 according to an embodiment of the present disclosure.

FIG. 17 is a block diagram of a stretchable display device according toan embodiment of the present disclosure.

Referring to FIG. 17, a stretchable display device according to anembodiment of the present disclosure may include a display panel 1710, atiming controller 1720, a stretch sensing unit 1730, a gate driving unit1740, a data driving unit 1750, and a memory 1760.

The display panel 1710 includes a plurality of pixels PX electricallyconnected to n gate lines GL1, . . . , GLn disposed in a firstdirection, and m data lines DL1, . . . , DLm disposed in a directionthat is different from the first direction. Accordingly, the pluralityof pixels PX display an image by a driving signal or a driving voltageapplied through the gate lines GL1, . . . , GLn and the data lines DL1,. . . , DLm.

The display panel 1710 includes an active area AA and a non-active areaNA adjacent to the active area AA. A plurality of pixels PX is disposedin the active area AA and an image is displayed on the basis ofgradation that each pixel PX displays. In each of the plurality ofpixels PX, a pixel circuit in which a light emitting element from whichlight is emitted and a plurality of driving elements for driving thelight emitting element are disposed is disposed. Because such a displaypanel 1710 is configured to be able to stretch, it may have a structurein which a second structure 112 made of a material that is more rigidthan a first substrate 111 may be disposed in an area where pixels PXare disposed on the first substrate 111 made of a stretchable material.

In one embodiment of FIG. 17, the pliable substrate 111 may be disposedonly under the light emitting elements of the active area AA. The NAthat is the rest of the display panel 1710 can be disposed on a morerigid substrate. Alternatively, the pliable substrate 111 may bedisposed under the entire display panel 1710 so that the circuits in theNA, even those who do not omit light, can be flexed and stretched.

The timing controller 1720 processes image data RGB that are input fromthe outside to be suitable for the size and resolution of the displaypanel 1710 and then supplies the image data to the data driving unit1750. The timing controller 1720 creates a plurality of gate controlsignals GCS and data control signals DCS using synchronous signals SYNC,for example, a dot clock signal DCLK, a data enable signal DE, ahorizontal synchronizing signal Hsync, and a vertical synchronizingsignal Vsync. Further, the timing controller 1720 receives a stretchdegree sensing value of the display panel 1710 sensed by the stretchsensing unit 1730 and creates an image compensation data cdata accordingto stretch of the display panel 1710 by comparing the received stretchdegree value and a lookup table stored in advance in the memory 1760,and may control the image compensation data to be applied to each pixelP through the data driving unit 1750.

The stretch sensing unit 1730 is electrically connected to a stretchsensing line 180S disposed in the display panel 1710 and may sense thedegree of stretch before and after stretch of the display panel 1710.The stretch sensing value SV sensed as such may be transmitted to thetiming controller 1720. The stretch sensing unit 1730, as describedabove, senses a capacitance difference before and after stretch betweena stretch sensing Rx line 180Sa and a stretch sensing Tx line 180Sbconstituting the stretch sensing line 180S and then may transmit asensed value to the timing controller 1720.

The gate driving unit 1740 supplies a gate signal to the n gate linesGL1, GLn in accordance with a gate control signal GCS supplied from thetiming controller 1720. In some embodiments, the gate signal may includeat least one scan signal SCAN and light emitting control signal EM.

A common gate driving unit may be configured in a type in which it isformed independently from a display panel and electrically connected tothe display panel in various ways. However, the gate driving unit 1740of a stretchable display device according to an embodiment of thepresent disclosure may be built in a Gate In Panel (GIP) manner on anon-active area NA in a thin film pattern shape in substratemanufacturing of the display panel 1710. Although FIG. 17 shows thatonly one gate driving unit 1740 is provided in a non-active area NA ofthe display panel 1710, the present disclosure is not limited theretoand two gate driving units 1740 may be disposed at both sides of anactive area AA.

Since the gate driving unit 1740 is disposed in built-in type in thedisplay panel 1710, a plurality of second substrates (112 of FIG. 1) maybe disposed in a space type over the first substrate (111 of FIG. 1) inthe non-active areas NA where the gate driving unit 1740 is disposed.That is, the gate driving unit 1740 may be made in a structure in whicha circuit constituting each stage constituting the gate driving unit1740 is disposed on the second substrate (112 of FIG. 1) and aconnecting line connecting each stage is disposed on the first substrate(111 of FIG. 1).

The data driving unit 1750 converts image data RGB and compensation datacdata into a data voltage in accordance with a data control signal DCSsupplied from the timing controller 1720 and supplies the converted datavoltage to pixels P through the m data lines DL1, . . . , DLm. Thevoltage provided as the data value for the light emitting pixel elementscan therefore be changed, whether to increase it or to decrease it tocompensate the stretching of the display. The memory 1760 may storecompensation data related to stretch of the display panel 1710 in a formof lookup table LUT. Although the memory 1760 is described as a separateconfiguration from the timing controller 1720 in an embodiment of thepresent disclosure, the memory 1760 is not limited thereto and may bemade as a configuration that is included in the timing controller 1720.The look up table can be created by performing a large number ofstretches while measuring the change needed in the data signal togenerate a light emitted at each pixel that has the same luminance valueand characteristics both when it stretched and when it is not stretched.The stretch value can be measure locally, for a small group of pixelsthat are undergoing stretch and the compensation amount cdata, can besupplied to only those pixels, or it can be measured for the flexibledisplay as a whole and applied to all active pixels on the display.

A method of sensing the degree of stretch of a stretchable displaydevice according to an embodiment of the present disclosure configuredas such is as follows.

FIG. 18 is a flowchart sequentially showing an image compensation methodof a stretchable display device according to an embodiment of thepresent disclosure.

The concepts disclosed herein include a method of sensing a stretchingof a substrate and measuring the amount of stretch on an active basis,namely, while the stretch is occurring. Steps of this method are alsoshown in FIG. 18 and are described below.

Referring to FIG. 18, the stretch sensing unit 1730 senses whetherstretch of the display panel 1710 has occurred (S1810). The stretchsense of the display panel 1710 may sense the degree of stretch of thedisplay panel 1710 in a period in which a data signal or a gate signalis not applied, in a case that a stretch sensing line senses panelstretch and transmits a data signal or a gate signal.

Further, when a stretch sensing line is separately disposed regardlessof signal transmission for stretch sensing, it may be made by control ofthe timing controller 1720 or may be configured to sense whether thereis stretch every set time.

Thereafter, when it is determined that stretch has been made by thestretch sensing unit 1730 (S1820), a sensing value of how much thedisplay panel 1710 has been stretched is calculated (S1830). In someembodiments, a stretch degree sensing value may be calculated through[Expression 1] on the basis of a capacitance difference before and afterstretch between the stretch sensing Rx line 180Sa and the stretchsensing Tx line 180Sb.

Such a stretch degree sensing value SV is transmitted to the timingcontroller 1720 and then the timing controller 1720 reads apredetermined reference value from the memory 1760 (S1840). In someembodiments, the predetermined reference value, as described above, maybe stored in a lookup table type in the memory 1760.

Thereafter, the timing controller 1720 creates compensation data cdataby comparing the predetermined reference value and the stretch degreesensing value (S1850) and applies the created compensation data cdata toeach pixel P through the data driving unit 1750 (S1860) such that imagedistortion by stretch of the display panel 1710 is compensated by thecompensation data, thereby being able to minimize deterioration of imagequality.

According to one embodiment, a method of sensing an amount of stretch ina stretchable display is carried out by the following steps. There is asensing a first reference value of stretch in a first substrate having afirst modulus of elasticity. The first substrate is the flexiblesubstrate 111 as described herein. There are plurality of rigidsubstrates 112 on the flexible substrate as described herein. After thisfirst reference value is obtained, the first substrate is stretched afirst distance. The second substrates are maintained as rigid andunstretched. As a result of the stretching, the second substrates aremoved second substrates a second distant from each other that is greaterthan the first distance. During the stretching the electrical connectionby a stretchable conductive line between the plurality of secondsubstrates prior to and after the stretching is maintained. After thestretching the amount of stretch from the first reference value issensed.

The method also includes generating a stretch compensation signal basedon the measured amount of stretch during the stretching. During thestretching, a light emission data signal is transmitted to the organiclight emitting diodes. In one embodiment, a timing controller thatcontrols the stretch sensing line will sense a degree of stretch in aperiod when the data signal is not applied and transmit the data signalto the organic light emitting diode in a period after the degree ofstretch has been sensed. A compensation signal to the data signal isgenerated based on the amount of stretch and the light emission datasignal that is transmitted to the organic light emitting diode duringthe stretching is modified based on the generated compensation signal.In one embodiment, a gate drive signal is transmitted to the at leastone transistor on the rigid substrate during the stretching.

After a period of time, the amount of stretch may increase and the stepsdescribed above and those shown in FIG. 18 are repeated. Also, after aperiod of time, the stretching may end and the first substrate isreturned to the unstretched shape after the stretching.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

The invention claimed is:
 1. A stretchable display device, comprising: adisplay panel having disposed thereon a plurality of pixels and aplurality of connecting lines respectively transmitting a driving signalto the plurality of pixels on a stretchable substrate; a stretch sensingcircuit sensing an amount of stretch of the display panel; a timingcontroller creating compensation data by comparing a sensing valuesensed by the stretch sensing circuit and a reference value; and a datadriving circuit receiving the compensation data from the timingcontroller and applying the compensation data to the display panel,wherein at least one of the plurality of connecting lines is a stretchsensing line configured to sense the amount of stretch of the displaypanel, and wherein the timing controller controls the stretch sensingline to transmit a data signal containing the amount of stretch in aperiod in which the data signal is applied when the stretch sensing lineis connected to a data line transmitting a data signal to the pixel, andto sense the amount of stretch of the stretch sensing line in a periodin which the data signal is not applied.
 2. The stretchable displaydevice of claim 1, wherein the stretch sensing circuit is connected tothe stretch sensing line.
 3. The stretchable display device of claim 2,wherein the stretch sensing line includes a stretch sensing Rx line anda stretch sensing Tx line for sensing the amount of stretch of thedisplay panel.
 4. The stretchable display device of claim 3, wherein thestretch sensing circuit senses the amount of stretch based on acapacitance difference before and after stretch between the stretchsensing Rx line and the stretch sensing Tx line.
 5. The stretchabledisplay device of claim 4, wherein the stretch sensing line has a curvedshape.
 6. The stretchable display device of claim 1, wherein thereference value includes image compensation values according to stretchdifference values stored in a lookup table.
 7. The stretchable displaydevice of claim 1, wherein the data driving circuit applies thecompensation data to respective driving signals that are transmitted onthe plurality of connecting lines on the display panel.
 8. A stretchabledisplay device, comprising: a display panel having disposed thereon aplurality of pixels and a plurality of connecting lines respectivelytransmitting a driving signal to the plurality of pixels on astretchable substrate; a stretch sensing circuit sensing an amount ofstretch of the display panel; a controller that receives data indicatingthe sensed amount of stretch of the of the display panel and generatescompensation data based on the sensed amount of stretch; and a datadriving circuit receiving the compensation data from the controller andapplying the compensation data to the display panel, wherein at leastone of the plurality of connecting lines is a stretch sensing lineconfigured to sense the amount of stretch of the display panel, andwherein the timing controller controls the stretch sensing line totransmit a data signal containing the amount of stretch in a period inwhich the data signal is applied when the stretch sensing line isconnected to a data line transmitting a data signal to the pixel, and tosense the amount of stretch of the stretch sensing line in a period inwhich the data signal is not applied.
 9. The stretchable display deviceof claim 8, wherein the stretch sensing circuit is connected to thestretch sensing line.
 10. The stretchable display device of claim 9,wherein the stretch sensing line includes a stretch sensing Rx line anda stretch sensing Tx line for sensing the amount of stretch of thedisplay panel.
 11. The stretchable display device of claim 10, whereinthe stretch sensing circuit senses the degree of stretch based on acapacitance difference before and after stretch between the stretchsensing Rx line and the stretch sensing Tx line.
 12. The stretchabledisplay device of claim 11, wherein the stretch sensing line has acurved shape.
 13. The stretchable display device of claim 8, wherein thedata driving circuit applies the compensation data to respective drivingsignals that are transmitted on the plurality of connecting lines on thedisplay panel.